Five types of mesoporous silica-based adsorbents were prepared by rationally implementing five diverse aminecontaining functional units into the mesoporous SBA-15 structures. The prepared materials were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorptionÀ desorption isotherms and thermogravimetric analysis. Among the five adsorbents, the ethylenediamine functionalized SBA-15, namely, AAPTMS-SBA-15, achieved the complete adsorption of Congo red (CR) at pH 6.0, with the maximum adsorption capacity of 4608 mg/g. The AAPTMS-SBA-15 materi-al was used effectively for CR adsorption from the individual and binary dye aqueous solutions, indicating that AAPTMS-SBA-15 can selectively remove and separate CR from wastewater. The hydrogen bonding interactions between AAPTMS-SBA-15 and CR were beneficial to the high selectivity and excellent adsorption capacity of AAPTMS-SBA-15 toward CR. Moreover, the selective adsorption and efficient separation of CR realized the recovery and reusability of AAPTMS-SBA-15 and CR, which can not only avoid secondary environmental pollution, but also save economic costs.

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